Agricultural spraying machine and method for spraying a phytosanitary liquid on land cultivated by means of such a machine

ABSTRACT

The invention relates to an agricultural machine for spraying a phytosanitary liquid over cultivated land, said machine comprising means for moving the machine, a spray boom having at least one arm, a mechanism for inclining the boom and/or at least one of the arms in relation to a frame of the machine and vertically when the machine is on a flat and horizontal surface, and a mechanism for raising/lowering the boom along an axis fixed in relation to the frame of the machine. At least one of the arms is provided with at least one sensor, each sensor measuring a distance between the surface of the land and said sensor or, if necessary, between the crop and the sensor. The control unit is connected to each sensor, provided with a memory for storing information provided by each sensor, and able to control the raising/lowering mechanism according to information stored in the memory.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.13/824,878, filed Jul. 22, 2013, which is a National Stage entry ofInternational Application No. PCT/FR2011/052295, filed Oct. 3, 2011,which claims the benefit of priority to French Patent Application No. 1058073, filed Oct. 5, 2010. The disclosures of the prior applications arehereby incorporated in their entirety by reference.

This invention relates to an agricultural spraying machine as well as amethod for spraying a phytosanitary liquid on a cultivated land by meansof such a machine.

It is known to use an agricultural machine provided with a spray boom inorder to spread a phytosanitary liquid on vegetation planted on landthat can comprise irregularities, for example holes or bumps, and ofwhich the slope can vary.

In order for the distribution of the phytosanitary liquid on thevegetation to be satisfactory, the boom must not be too far from thevegetation, in such a way as to avoid the dispersion of drops ofphytosanitary liquid into the atmosphere. Moreover, if the boom is tooclose to the land, it risks colliding with the land and/or thevegetation, which would damage the spray boom and which could plug upthe spraying nozzles of the boom.

Traditionally, an agricultural spraying machine is provided withcylinders in order to incline and raise or lower its spray boom inrelation to its frame, which allows the boom to adapt to the variationsin the geometry of the land. The user, when the agricultural machinesprays the phytosanitary liquid on the vegetation, manually controls theelevation of the spray boom, i.e. its inclination, and the height of thespray boom, so that it is not too close or too far from the vegetationor the land.

However, when the user sprays the phytosanitary liquid on thevegetation, manually controlling the inclination and the height of theboom is not easy because the user must simultaneously control themachine, for example a tractor, along a trajectory. When the boomcomprises several articulated arms, the controlling is even moredifficult because the user manually controls the variable geometry ofthe boom, i.e. the inclination of the various arms. In addition, theuser always aims to go as quickly as possible and cannot afford toreduce the speed of the machine.

According to another aspect, due to the inertia of the boom whichremains tilted in order to not transfer the irregularities of the landunder the wheels of the machine, each modification in the elevation ofthe boom, and where applicable in its variable geometry, results in amoving of the centre of gravity and a tipping of the boom beyond theangle corrected manually by the user. This causes oscillations, similarto those of a pendulum, which can thrust one of the ends of the boominto the land. These oscillations can, furthermore, complicate and slowdown the correct adjustment of the correction for the elevation and/orthe variable geometry of the boom. This disadvantage is also present inthe known systems for automatic elevation correction, such as the onedescribed in document DE-A.-41 40 254.

It is these disadvantages that the invention intends more particularlyto overcome by proposing an agricultural spraying machine and a methodfor spraying allowing for easy and optimised spraying, and which limitsthe risks of collision between the boom and the land or between the boomand vegetation planted on the land.

To this effect, the invention relates to an agricultural machine forspraying an phytosanitary liquid on a cultivated land, comprising

-   -   means for moving the machine over a surface of the land,    -   a spray boom for spraying the phytosanitary liquid comprising at        least one arm,

a mechanism for inclining the boom and/or at least one of the arms inrelation to a frame of the agricultural machine,

-   -   a mechanism for raising/lowering the boom according to a fixed        axis in relation to the frame of the agricultural machine and        vertical, and even substantially vertical, when the agricultural        machine is on a flat and horizontal surface and    -   a control unit.

At least one of the arms of the boom is provided with at least onesensor, each sensor measuring a distance between the surface of the landand this sensor or, where applicable, between vegetation planted in theland and this sensor. The control unit is connected to each sensor,provided with a storage memory for the information provided by eachsensor and able to control the mechanism for raising/lowering dependingon the information stored in the memory.

Thanks to the invention, when a point of the spray boom is too close tothe land or the vegetation, i.e. at a distance less than a predeterminedminimum safety distance, the control unit controls the mechanism forraising/lowering so that it raises the boom automatically to apre-programmed distance. Inversely, the control unit can also controlthe mechanism for raising/lowering so that it lowers the boom to apre-programmed distance, when its point closest to the vegetation or theland is farther away from vegetation or the land than a pre-programmedmaximum distance. This allows the user to manually control theinclination of each arm of the boom, while still ensuring that the pointof the boom which is closest to the land or the vegetation is maintainedautomatically at a distance which is, on the one hand, at least equal tothe minimum safety distance, which avoids the risks of collision betweenthe boom and the land or the vegetation, and, on the other hand, lessthan the pre-programmed maximum distance, which avoids the dispersion ofthe phytosanitary liquid into the atmosphere.

According to advantageous but not mandatory aspects of the invention,such an agricultural machine can incorporate one or several of thefollowing characteristics, taken in any combination technicallypermissible:

-   -   It is provided with a manual control system for controlling the        mechanism for raising/lowering and/or for controlling at least        one mechanism for inclining.    -   The control unit is able to control at least one mechanism for        inclining depending on the information stored in the memory.    -   At least one of the arms of the boom is provided with at least        two sensors.

The invention also has for purpose a method for spraying a phytosanitaryliquid on cultivated land, by means of a machine according to theinvention. This method comprises steps wherein:

a1) before the spraying, the user enters into the control unit the valueof a minimum distance,

b1) during the spraying, as soon as the distance measured by at leastone sensor is less than the minimum distance predetermined in step a1),the control unit controls the mechanism for raising/lowering the boom inorder to rapidly separate the boom from the surface until the distancemeasured by this or these sensors is equal to the minimum distancepredetermined in step a1).

The invention also has for purpose a second method for spraying aphytosanitary liquid on cultivated land, by means of a machine accordingto the invention. This method comprises steps wherein:

a2) before the spraying, the user enters into the control unit the valueof a minimum distance and the value of an intermediate distance greaterthan the minimum distance,

b2) during the spraying, as soon as the distance measured by at leastone sensor is less than the minimum distance predetermined in step a2),the control unit controls the mechanism for raising/lowering the boom inorder to rapidly separate the boom from the surface until the distancemeasured by this or these sensors is equal to the intermediate distancepredetermined in step a2).

The invention also has for purpose a third method for spraying aphytosanitary liquid on cultivated land, by means of a machine accordingto the invention. This method comprises steps wherein:

a3) before the spraying, the user enters into the control unit the valueof a minimum distance, the value of a maximum distance and the value ofan intermediate distance between the minimum distance and the maximumdistance,

b31) during the spraying, as soon as the distance measured by at leastone sensor is less than the minimum distance predetermined in step a3),the control unit controls the mechanism for raising/lowering the boom inorder to rapidly separate the boom from the surface until the distancemeasured by this or these sensors is equal to the intermediate distancepredetermined in step a3), b32) during the spraying, as soon as thedistance d measured by each sensor is greater than the maximum distancepredetermined in step a3), the control unit controls the mechanism forraising/lowering the boom in order to bring the boom closer to thesurface until the distance measured by at least one sensor is equal tothe intermediate distance predetermined in step a3).

According to advantageous but not mandatory aspects of the invention,such methods can incorporate one or several of the followingcharacteristics, taken in any combination technically permissible:

-   -   They include an additional step c1), after the steps a1), a2)        and a3) and without priority in relation to steps b1), b2) and        b31) wherein the user uses the system for manually controlling        the mechanism for raising/lowering in order to separate the boom        from or bring it closer to the surface and/or uses the system        for manually controlling at least one mechanism for inclining in        order to incline at least one of the arms.    -   They include an additional step c2), after the steps a 1), a2)        and a3) and without priority in relation to steps b1), b2) and        b31), wherein the control unit controls at least one mechanism        for inclining in such a way that each arm associated with this        or these inclination mechanisms is globally parallel to a        portion of the surface located to the vertical of this arm.    -   The minimum distance is between 30 cm and 70 cm, preferably of a        magnitude of 50 cm.    -   The maximum distance is between 70 cm and 150 cm, preferably of        a magnitude of 100 cm.    -   The intermediate distance is between 50 cm and 100 cm,        preferably of a magnitude of 70 cm.

The invention shall be better understood and other advantages of thelatter shall appear more clearly when reading the following descriptionof an agricultural spraying machine and of a method for sprayingaccordance with its principle, provided solely by way of example and inreference to the annexed drawings wherein:

FIG. 1 is a rear view of an agricultural machine according to theinvention;

FIG. 2 is a perspective view that diagrammatically shows the machine ofFIG. 1; and

FIG. 3 is a view similar to FIG. 1 of an agricultural machine inaccordance with a second embodiment of the invention.

FIG. 1 shows an agricultural machine 1 for spraying a phytosanitaryliquid which is provided with a spray boom 2 located to the rear of themachine 1. Alternatively, the boom 2 is located in front of the machine1. The machine 1 is also provided with a motor not shown which belongsto means for moving the machine 1 on land, with a transmission, asteering wheel 11 and wheels 10. The machine 1 is thereforeself-propelled and autonomous, but alternatively the boom 2 is supportedby a trailer hitched to any self-propelled machine. The machine 1 is atractor, but other machines can be used.

As shown in FIG. 2, whereon the machine 1 is shown diagrammatically, X1denotes a transversal axis of the machine 1, perpendicular to itsforward motion in a straight line, Y1 a longitudinal axis of a frame 12of the machine 1, parallel to its forward motion in a straight line, andZ1 an axis of the machine 1 perpendicular to the axes X1 and Y1. Theaxes X1, Y1 and Z1 are fixed in relation to the frame 12 of the machine1.

In FIGS. 1 and 2, the machine 1 is on the surface S of a flat andhorizontal land wherein vegetation, not shown, can be cultivated. Theframe 12 of the machine 1 is therefore horizontal, and even slightlyinclined upwards, and the axis Z1 is then vertical, and even slightlyinclined to the side. The axis Z1 is therefore vertical or substantiallyvertical. However, when the inclination of the surface S varies, theaxis Z1 is inclined in relation to the vertical.

In the rest of the description, the elements qualified as lower arecloser to the surface S than the elements qualified as upper.

The boom 2 comprises a single arm 2 a which extends along a longitudinalaxis X2, substantially parallel to the axis X1 when the machine 1 is onflat and horizontal land. Means for spraying 22 are distributed on theboom 2, along the longitudinal axis X2, and project a phytosanitaryliquid onto the surface S.

In an alternative not shown, the boom 2 can include several sectionsarticulated together around axes parallel to the axis Z1, in such a waythat it is possible to fold back the boom 2 in order to reduce itslength, which is advantageous when the machine 1 is travelling on anarrow road.

The boom 2 is provided with two sensors 6, a first sensor 6 located on afirst end 24 of the boom 2, and a second sensor 6 located on the otherend 26 of the boom 2. Each sensor 6 makes it possible to measure adistance d between this sensor 6 and the surface S or, where applicable,between this sensor 6 and vegetation planted in the land. The sensors 6and the means for spraying 22 are located substantially in the sameplane perpendicular to the axis Z1. In FIG. 1, as the longitudinal axisX2 of the boom 2 is parallel to the surface S, the distances d measuredby each sensor 6 are identical.

In an alternative not shown, the sensors 6 and the means for spraying 22are located in a plane that is slightly inclined in relation to a planeperpendicular to the axis Z1. In addition, the sensors 6 can be offsetaccording to the axis Z1 in relation to the means for spraying 22. Inthis case, the control unit 5 is informed of this offset.

A connecting rod 8, parallel to the axis Z1 in the configuration of FIG.1, is articulated in rotation, on its lower end, with the boom 2, aroundan axis Y2 parallel to the axis Y1. The upper end of the connecting rod8 is articulated in rotation, around an axis Y9 parallel to the axis Y1,with a slideway 9. The slideway 9 is mobile in translation according tothe axis Z1 in relation to the frame 12 of the machine 1. To do this,the slideway 9 cooperates with two rails 11 and 11′ parallel to the axisZ1 and which are fixed to the frame 12. The rails 11 and 11′ are locatedon either side of the axis Z1.

The machine 1 is provided with a mechanism for inclining the boom 2 in aplane X1-Z1 perpendicular to the forward direction Y1 of the machine 1.The plane X1-Z1 is parallel to the axes X1 and Z1. The mechanism forinclining allows for the inclination of the boom 2 in relation to theframe 12 of the machine 1 and comprises a first cylinder 3 which can behydraulic or electrical, but other actuators can be suitable.

The first cylinder 3 comprises a rod 32 and a body 34. The rod 32comprises an upper end, located opposite the body 34, articulated inrotation with the connecting rod 8 around an axis Y8 parallel to theaxis Y1 and located in the vicinity of the axis Y9. The body 34 of thefirst cylinder 3 is connected to the boom 2 by a bar 36. A lower end ofthe bar 36, opposite the body 34 of the cylinder 3, is articulated inrotation with the boom 2 around an axis Y3 parallel to the axis Y1. Theaxis Y3 is offset along the longitudinal axis X2 of the boom 2 inrelation to the axis Y2. The cylinder 3 therefore allows for theinclination of the boom 2 around the axis Y2.

The machine 1 is also provided with a mechanism for raising/lowering theboom 2 according to the axis Z1. The mechanism for raising/loweringcomprises a second cylinder 30 which can be hydraulic or electrical, butother actuators can be suitable.

The second cylinder 30 comprises a rod 32′ and a body 34′. The rod 32′comprises an upper end which is located opposite the body 34′ of thecylinder 30 and which is articulated in rotation with the machine 1around the axis Y1.

The body 34′ of the second cylinder 30 is connected to the slideway 9 bya bar 36′. A lower end of the bar 36′, opposite the body 34′ of thesecond cylinder 30, is articulated in rotation with the slideway 9around an axis Y9′ parallel to the axis Y1. The axes Y1, Y2, Y9 and Y9′are aligned along the axis Z1.

α denotes an angle defined between the axis Z1 and the longitudinal axisX2 of the boom 2 in a plane perpendicular to the axis Y1. The angle α islocated, in FIG. 1, in the upper right quadrant. In the configuration ofFIG. 1, the angle α is equal to 90°.

The translation of the rod 32′ of the second cylinder 30 causes thetranslation of the boom 2 according to the axis Z1, by the intermediaryof the connecting rod 8 and of the slideway 9, which moves closer orseparates the boom 2 from the surface S.

The translation of the rod 32 of the first cylinder 3 causes theinclination of the longitudinal axis X2 of the boom 2 in relation to theaxis Z1, i.e. the variation of the angle α. In other words, the firstcylinder 3 allows for the rotation of the boom 2 in the plane X1-Z1,around the axis Y2.

The machine 1 is provided with a control unit 5 which includes a memory52 for storing information.

The sensors 6 are connected to the control unit 5 by wired connectionsnot shown which allow the sensors 6 to transmit to the control unit 5information concerning the values that they are measuring.Alternatively, the means of connecting between the sensors 6 and thecontrol unit 5 are wireless.

The machine 1 is provided with an optional manual system for controllingthe first cylinder 3. The manual control system comprises, for example,a first controller 38 placed in the cabin of the machine 1 in thevicinity of the steering wheel 11. The first controller 38 is connectedto the first cylinder 3 by a first wired connection 51.

The manual system for controlling the first cylinder 3 allows the userto vary the angle α, i.e. to vary the inclination of the boom 2 in theplane X1-Z1 in relation to the axis Z1, with the purpose of making itparallel to the surface S.

In addition, the first cylinder 3 is, optionally, connected to thecontrol unit 5 by a wired connection 50 which makes it possible for thecontrol unit 5 to control the first cylinder 3.

In such a way as to ensure its controlling, the first cylinder 3 isconnected to the control unit 5 and/or to the controller 38.

The second cylinder 30 is connected to the control unit 5 by a wiredconnection 50′ which allows the control unit 5 to control the secondcylinder 30.

The machine 1 is also provided with an optional manual system forcontrolling the second cylinder 30. This manual control systemcomprises, for example, a second controller 38′ placed in the cabin ofthe machine 1 in the vicinity of the steering wheel 11. The secondcontroller 38′ is connected to the second cylinder 30 by a wiredconnection 51′.

Alternatively, the wired connections 50, 50′, 51 and 51′ are wireless.

The cabin of the machine 1 is configured in such a way that the user cansimultaneously control the means for moving the machine 1, with thesteering wheel 11, and the manual systems for controlling the firstcylinder 3 and the second cylinder 30, i.e. the controllers 38 and 38′.

The rest of the description relates to a first method for spraying aphytosanitary liquid on vegetation planted in the land, by means of themachine 1.

Before the spraying and in a step a1), the user enters into the controlunit 5 the value of a minimum distance d_(min). The minimum distanced_(min) can be between 30 cm and 70 cm, preferably of a magnitude of 50cm.

During the spraying and in a step b1), following step a1), as soon asthe distance d measured by at least one sensor 6 is less than theminimum distance d_(min) predetermined in step a1), the control unit 5rapidly and automatically controls the second cylinder 30 in order toseparate the boom 2 from the surface S until the distance d measured bythis or these sensors 6 is equal to the minimum distance d_(min)predetermined in step a1). The rapid controlling of the raising of theboom 2 makes it possible to prevent the risks of collision between theboom 2 and the land or the vegetation. For example, the control unit 5can control the second cylinder 30 in such a way that the translationtime of the rod 32′ of the second cylinder 30 is of a magnitude of a fewseconds.

As such, as soon as the boom 2 is too close to the surface S, it isautomatically raised. This makes it possible to prevent the boom 2 fromentering into collision with the land or, where applicable, with thevegetation planted in the land. In this way, the boom 2 and the meansfor spraying 22 do not risk becoming damaged. Moreover, this allows theuser to more serenely control the trajectory of the machine 1 whilestill manually controlling the first cylinder 3 easily, without havingto provide excessive vigilance as to the risks of collision.

The rest of the description relates to a second method for spraying aphytosanitary liquid on vegetation planted in the land, by means of themachine 1.

In a step a2) and before the spraying, the user enters into the controlunit 5 the value of a minimum distance d_(min) and the value of anintermediate distance d_(int) greater than the minimum distance d_(min).

The intermediate distance d_(int) can be between 50 cm and 100 cm,preferably of a magnitude of 70 cm.

Then, during the spraying and in a step b2), as soon as the distance dmeasured by at least one sensor 6 is less than the minimum distanced_(min) predetermined in step a2), the control unit 5 controls thesecond cylinder 30 in order to rapidly and automatically separate theboom 2 from the surface S until the distance d measured by this or thesesensors 6 is equal to the intermediate distance d_(int) predetermined instep a2).

For example, the control unit 5 can control the second cylinder 30 insuch a way that the translation time of the rod 32′ of the secondcylinder 30 is of a magnitude of a few seconds.

In this way, as soon as the boom 2 is too close to the surface S, thecontrol unit controls the second cylinder 30 in such a way as toadvantageously position the boom 2 at the intermediate distance d_(int),which corresponds to a satisfactory spraying distance.

The rest of the description relates to a third method for spraying aphytosanitary liquid by means of the machine 1.

In a step a3) and before the spraying, the user enters into the controlunit 5 the value of a minimum distance d_(min), the value of a maximumdistance d_(max) and the value of an intermediate distance d_(int)between the minimum distance d_(min) and the maximum distance d_(max).

The maximum distance d_(max) can be between 70 cm and 150 cm, preferablyof a magnitude of 100 cm.

Then, during the spraying and in a step b31) after the step a3), as soonas the distance d measured by at least one sensor 6 is less than theminimum distance d_(min) predetermined in step a3), the control unit 5automatically and rapidly controls the second cylinder 30 in order toseparate the boom 2 from the surface S until the distance d measured bythis or these sensors 6 is equal to the intermediate distance d_(int)predetermined in step a3). For example, the control unit 5 can controlthe second cylinder 30 in such a way that the translation time of therod 32′ of the second cylinder 30 is of a magnitude of a few seconds.

As such, as soon as the boom 2 is too close to the surface S or to thevegetation, the control unit 5 automatically separates the boom 2 intoan intermediate position for optimum spraying.

During the spraying and in a step b32) after the step a3), as soon asthe distance d measured by each sensor 6 is greater than the maximumdistance d_(max) predetermined in step a3), the control unit 5automatically controls the second cylinder 30 in order to bring the boom2 closer to the surface S, until the distance d, measured by at leastone of the sensors 6, is equal to the intermediate distance d_(int),predetermined in step a3).

As such, as soon as the boom 2 is too far from the surface S or from thevegetation, the control unit 5 automatically brings the boom 2 closerinto an intermediate position for optimum spraying.

The steps b1), b2) and b31) have priority in relation to the optionalsteps described hereinbelow because the steps b1), b2) and b31) make itpossible to prevent the collision of the boom 2 with the land or thevegetation, which is essential.

In a step c1) which is optional, which can be implemented for the first,second and third methods described hereinabove, and which is after thesteps a1), a2) and a3), the user uses the manual control system 38′ ofthe second cylinder 30 in order to bring the boom 2 closer to thesurface S. In this case, once the risks of collision have been avoided,i.e. once the control unit 5 has automatically controlled the mechanismfor raising/lowering 30 during the step b1), b2) or b31), the user athis discretion brings the boom 2 closer to the surface S.

Inversely, in the step c1) the user can also user the manual controlsystem 38′ of the second cylinder 30 in order to separate the boom 2from the surface S or the vegetation, for example if he anticipates animminent risk of collision.

The step c1) does not have priority in relation to the steps b1), b2)and b31), i.e. the user cannot use the manual control system 38′ of thesecond cylinder 30 to position the boom 2 at a distance d less thand_(min). As the steps b₁), b2) and b31) have priority before the stepc1), as soon as the distance d measured by at least one sensor 6 is lessthan d_(min), the control unit 5, in the step b1), b2) or b31),separates the boom 2 from the surface S or from the vegetation so thatthe distance d measured by the sensor 6 is, according to the method,greater than or equal to d_(min).

Moreover, insofar as the distance d measured by each sensor 6 remainsgreater than or equal to the minimum distance d_(min), the manualcontrol of the mechanism for inclining 3 and of the mechanism forraising/lowering 30, decided by the user, takes effect immediately andhas priority before the actions controlled by the control unit 5 otherthan the actions of the steps b1), b2) and b31). Indeed, the steps b1),b2) and b31) make it possible to prevent the thrusting of the boom 2into the land or the vegetation, which is essential.

In a step c2) which is optional, which can be implemented in the first,second and third methods described hereinabove and which is after thesteps a1), a2) and a3), the control unit 5 controls the first cylinder 3in such a way as to position the boom 2 globally parallel to a portionof the surface S located to the vertical of the boom 2. For example, thecontrol unit can control the first cylinder 3 in such a way that thedistances d measured by each sensor 6 are globally equal. The step c2)does not have priority before the steps b1), b2) and b31), i.e. in thestep c2), when the control unit 5 controls the first cylinder 3, itcannot position the boom 2 at a distance d less than or equal tod_(min).

Advantageously, in the step c2), the control unit 5 controls the firstcylinder 3 in such a way that the distance d measured by a minimum ofsensors 6 is greater than the maximum distance d_(max).

FIG. 3 corresponds to a second embodiment of the invention wherein themachine 1 is provided with a spraying boom 2 which comprises threearticulated arms 2 a, 2 b and 2 c. In FIG. 3, the elements similar tothose of FIG. 1 bear the same reference numbers to which is possiblyadded either the letter “a”, in the case where the element relates tothe arm 2 a, or the letter “b”, in the case where the element relates tothe arm 2 b, or the letter “c” in the case where the element relates tothe arm 2 c.

The arm 2 a is centred on the axis Z1 and is located between the firstarm 2 b and the second arm 2 c. The arm 2 a constitutes a “centralframe” for the boom 2.

X2 a denotes a longitudinal axis of the central frame 2 a, X2 b alongitudinal axis of the first arm 2 b and X2 c a longitudinal axis ofthe second arm 2 c.

The central frame 2 a of the boom 2 is connected to the machine 1 by astructure similar to that described in reference to the firstembodiment. This structure comprises a first cylinder 3 a, whichcorresponds to the cylinder 3 of FIG. 1, as well as a connecting rod 8,a slideway 9, two rails 11 and 11′ and a second cylinder 30, analogousto the elements bearing the same references in FIG. 1.

αa denotes an angle located on the side of the second arm 2 c inrelation to the axis Z1 and defined in a plane X2 a-Z1, between the axesX2 a and Z1. In FIG. 1, the angle αa is located in the upper rightquadrant. The plane X2 a-Z1 passes through the axes X2 a and Z1 and isperpendicular to the forward direction Y1 of the machine 1.

The first arm 2 b is articulated in rotation with a first axial end 24of the central frame 2 a around an axis Yb parallel to the axis Y1. Todo this, the central frame 2 a is provided with an element 21 thatcooperates with an element 21 b, fixed on a first end 24 of the firstarm 2 b, in order to form the articulation. The machine 1 is providedwith a cylinder 3 b of which a first end is articulated in rotation,around an axis Y3 b, with the arm 2 b and of which a second end isarticulated in rotation, around an axis Y2 b, with the central frame 2a. The axes Y2 b and Y3 b are parallel to the axis Y1.

Zb denotes a first reference axis, fixed in relation to the frame 12 ofthe machine 1, parallel to the axis Z1. In FIG. 3, the axis Zb isconfounded with the axes Yb and Y2 b. However, when the boom 2 isinclined, the axis Zb no longer passes through the axes Yb and Y2 b.

The second arm 2 c is articulated in rotation with a second axial end 26of the central frame 2 a around an axis Yc parallel to the axis Y1. Todo this, the central frame 2 a is provided with an additional element 21that cooperates with an element 21 c, fixed on a first end 24 of thesecond arm 2 c, in order to form the articulation. The machine 1 isprovided with an additional cylinder 3 c of which a first end isarticulated in rotation, around an axis Y3 c, with the arm 2 c and ofwhich a second end is articulated in rotation, around an axis Y2 c, withthe central frame 2 a.

Zc denotes a second reference axis, fixed in relation to the frame 12 ofthe machine 1, parallel to the axis Z1. In FIG. 3, the axis Zc isconfounded with the axes Yc and Y2 c. However, when the boom 2 isinclined, the axis Zc no longer passes through the axes Yc and Y2 c.

The translation of the rod of the cylinder 3 b or 3 c causes theinclination of the arm 2 b or 2 c in the plane X2 a-Z1, around the axisYb or Yc, in relation to the reference axis Zb or Zc and therefore inrelation to the axis Z1. The cylinders 3 a, 3 b and 3 c therefore makeit possible to incline the arms 2 a, 2 b and 2 c in relation to theframe 12 of the machine 1.

αb denotes an angle located on the side of the arm 2 b in relation tothe axis Zb and defined in the plane X2 a-Z1, between the axes Zb and X2b. αc denotes an angle located on the side of the arm 2 c in relation tothe axis Zc and defined between the axes Zc and X2 c. In theconfiguration of FIG. 3, the angles αa, αb and αc are equal to 90°. Theangles αb and αc correspond to the inclination of the arms 2 b and 2 cin the plane X2 a-Z1, in relation to the axis Z1.

Each arm 2 a, 2 b and 2 c is provided with two sensors 6 a, 6 b or 6 cwhich are located on each axial end 24 and 26 of the arms 2 a, 2 b or 2c and which each measure their own distance d, as shown in FIG. 3.

The machine 1 is provided with a manual system for controlling cylinders3 a, 3 b and 3 c which allows the user to separately control thecylinders 3 a, 3 b and 3 c. This manual control system comprises a firstcontroller 38 a, a second controller 38 b and a third controller 38 c.The first controller 38 a is connected to the cylinder 3 a by a wiredconnection 50 a which allows the user to manually control theinclination of the central frame 2 a, i.e. to vary the angle αa. Thesecond controller 38 b is connected to the cylinder 3 b by a wiredconnection 50 b which allows the user to manually control theinclination of the arm 2 b, i.e. to vary the angle αb.

The third controller 38 c is connected to the cylinder 3 c by a wiredconnection 50 c which allows the user to manually control theinclination of the arm 2 c, i.e. to vary the angle αc.

The machine 1 is provided with a manual control system 38′ of thecylinder 30 which comprises a controller 38′ connected to the cylinder30 by a wired connection 51′.

The wired connections 50 a, 50 b, 50 c and 51′ can be wireless.

The machine 1 is provided with a control unit 5 which comprises a memory52 and which is connected to the cylinder 30 by a wired connection 50′.Each sensor 6 a, 6 b and 6 c is connected to the control unit 5 by wiredconnections not shown. These connections can also be wireless.

The method of spraying a phytosanitary liquid by means of the machine 1in accordance with the second embodiment is similar to the methoddescribed in reference to the first embodiment. However, during thesteps b1, b2), b31), b32) and c2), the sensors 6 a, 6 b and 6 c of eacharm 2 a, 2 b and 2 c are taken into account.

In particular, during the steps b1, b2), b31), b32) and c2), the controlunit 5 controls the mechanism for raising/lowering 30 according to thedistances measured by each sensor 6 a, 6 b and 6 c.

During the step c1), the user can use the manual control system 38′ ofthe cylinder 30 insofar as the distance d measured by each sensor 6 a, 6b and 6 c is greater than or equal to the distance d_(min).

During the step c2), the control unit 5 controls at least one cylinder 3a, 3 b or 3 c in such a way that the arm 2 a, 2 b or 2 c associated tothe cylinder 3 a, 3 b or 3 c is globally parallel to a portion of thesurface S located to the vertical of the arm 2 a, 2 b or 2 c, insofar asthe distance d measured by each sensor 6 a, 6 b and 6 c is greater thanor equal to the distance d_(min). For example, the control unit 5 cancontrol the cylinder 3 b and the cylinder 3 c in such a way that thearms 2 b and 2 c are globally parallel to portions of the surface Slocated to the vertical of the arms 2 b and 2 c, insofar as thedistances d measured by the sensors 6 b and 6 c are greater than orequal to the distance d_(min).

In other embodiments of the invention, not shown, the number and thelocation of the sensors 6, 6 a, 6 b and 6 c on the boom 2 can vary. Forexample, in the case of a machine 1 of which the boom 2 comprises acentral frame 2 a and two arms 2 b and 2 c located on either side of thecentral frame 2 a, as shown in FIG. 3, the central frame 2 a cancomprise only one central sensor 6 a, and the arms 2 b and 2 c can eachcomprise only one end sensor 6 b or 6 c, located opposite the centralframe 2 a.

Moreover, the boom 2 can comprise a variable number of arms. Forexample, on each side of the central frame 2 a, the boom 2 can comprisetwo arms articulated together.

On the other hand, the mechanisms for inclination, raising/lowering andthe system for hooking the boom 2 to the frame 12 of the machine 1 showare not restrictive, as the invention can be implemented for machinesthat are different from the tractors shown in the figures. For example,the mechanism for raising/lowering can be of the deformable doubleparallelogram type.

The manual control systems 38, 38 a, 38 b and 38 c inclinationmechanisms 3, 3 a, 3 b and 3 c are optional, given that the control unit5 is able to control the inclination mechanisms 3, 3 a, 3 b and 3 c. Assuch, in an embodiment of the invention, the control unit 5 controlsboth the mechanism for raising/lowering 3 and each mechanism forinclining 30, without the user manually controlling these mechanisms 3and 30.

Furthermore, the embodiments shown are not restrictive and theircharacteristics can be combined.

The invention claimed is:
 1. Method for spraying phytosanitary liquid oncultivated land by means of an agricultural machine, said machine beingmovable on a surface of the cultivated land and comprising: at least onespray arm for spraying a phytosanitary liquid onto the surface or ontovegetation planted thereon, at least one inclining actuator forinclining the arm relative to a frame of the machine, at least oneraising/lowering actuator for raising/lowering the arm in translationrelative to the frame, at least one sensor provided on the arm formeasuring a sensor distance value between said sensor and the surface orvegetation planted thereon, a control unit, configured to automaticallycontrol the inclining actuator and the raising/lowering actuator duringthe spraying, depending on the sensor distance value, auser-configurable minimum distance value, and a user-configurableintermediate distance value greater than the user-configurable minimumdistance value, wherein the method comprises the following steps: b2)during the spraying, as soon as the sensor distance value measured bythe sensor is less than the user-configurable minimum distance value,the control unit controls the raising/lowering actuator in order toseparate the arm from the surface or from vegetation planted thereon,until the sensor distance value measured by said sensor is equal to theuser-configurable intermediate distance value, and c2) during thespraying, without priority in relation to b2), the control unit controlsthe inclining actuator in such a way that the arm is approximatelyparallel to the surface.
 2. Method for spraying according to claim 1,wherein the method comprises a step a2) as follows: before the spraying,a user configures the minimum distance value and the intermediatedistance value into the control unit.
 3. Method for spraying accordingto claim 2, wherein the user-configurable minimum distance value isbetween 30 cm and 70 cm and wherein the user-configurable intermediatedistance value is between 50 cm and 100 cm.
 4. Method for sprayingaccording to claim 1, wherein: the control unit is configured toautomatically control the inclining actuator and the raising/loweringactuator during the spraying, depending on a user-configurable maximumdistance value, wherein the method comprises a further step b32), asfollows: during the spraying, as soon as the sensor distance valuemeasured by the sensor is greater than the user-configurable maximumdistance value, the control unit controls the raising/lowering actuatorin order to bring the arm closer to the surface, until the sensordistance value measured by said sensor is equal to the user-configurableintermediate distance value, and step c2) is performed without priorityin relation to step b32).
 5. Method for spraying according to claim 4,wherein the method comprises a further step a3) as follows: before thespraying, a user configures the maximum distance value into the controlunit.
 6. Method for spraying according to claim 5, wherein theuser-configurable maximum distance value is between 70 cm and 150 cm. 7.Method for spraying according to claim 1, wherein the machine furthercomprises a manual control system for controlling the raising/loweringactuator and the inclining actuator, and wherein the method includes afurther step c1), without priority to step b2), wherein a user uses themanual control system in order to separate or bring the arm closer tothe surface by means of the raising/lowering actuator and/or in order toincline the arm by means of the inclining actuator.
 8. Method forspraying according to claim 1, wherein the machine is provided only withone single arm forming a spray boom of the machine.
 9. Method forspraying according to claim 1, wherein: the machine is provided withseveral arms forming a spray boom of the machine, one of the armsforming a central frame of the boom and the other arms being articulatedarms relative to the central frame, the raising/lowering actuator isconfigured for raising/lowering said arms by raising/lowering thecentral frame of the boom in translation relative to the frame of themachine, and the machine is provided with several inclining actuatorsconfigured for inclining each of the articulated arms relative to thecentral frame and configured for inclining the boom relative to theframe of the machine by means of the central frame.
 10. Agriculturalmachine, said machine being movable on a surface of a cultivated land,the machine comprising: at least one spray arm for spraying aphytosanitary liquid onto the surface or onto vegetation plantedthereon, at least one inclining actuator for inclining the arm relativeto a frame of the machine, at least one raising/lowering actuator forraising/lowering the arm in translation relative to the frame, at leastone sensor provided on the arm for measuring a sensor distance valuebetween said sensor and the surface or vegetation planted thereon, acontrol unit, configured to automatically control the inclining actuatorand the raising/lowering actuator during the spraying, depending on thesensor distance value, a user-configurable minimum distance value, and auser-configurable intermediate distance value greater than theuser-configurable minimum distance value, wherein the control unit isconfigured so that: b2) during the spraying, as soon as the sensordistance value measured by the sensor is less than the user-configurableminimum distance value, the control unit controls the raising/loweringactuator in order to separate the arm from the surface or fromvegetation planted thereon, until the sensor distance value measured bysaid sensor is equal to the user-configurable intermediate distancevalue, and c2) without priority in relation to b2), the control unitcontrols the inclining actuator in such a way that the arm is globallyparallel to the surface.
 11. Agricultural machine according to claim 10,wherein the control unit is further configured so that: a2) before thespraying, a user may configure the minimum distance value and theintermediate distance value into the control unit.
 12. Agriculturalmachine according to claim 11, wherein the user-configurable minimumdistance value is between 30 cm and 70 cm and wherein theuser-configurable intermediate distance value is between 50 cm and 100cm.
 13. Agricultural machine according to claim 10, wherein: the controlunit is configured to automatically control the inclining actuator andthe raising/lowering actuator during the spraying, depending on auser-configurable maximum distance value, wherein the control unit isconfigured so that: b32) during the spraying, as soon as the sensordistance value measured by the sensor is greater than theuser-configurable maximum distance value, the control unit controls theraising/lowering actuator in order to bring the arm closer to thesurface, until the sensor distance value measured by said sensor isequal to the user-configurable intermediate distance value, and thecontrol unit is configured to perform step c2) without priority inrelation to step b32).
 14. Agricultural machine according to claim 13,wherein the control unit is configured so that: a3) before the spraying,a user may configure the maximum distance value into the control unit.15. Agricultural machine according to claim 14, wherein theuser-configurable maximum distance value is between 70 cm and 150 cm.16. Agricultural machine according to claim 10, wherein the machinefurther comprises a manual control system for controlling theraising/lowering actuator and the inclining actuator, and wherein themanual control system is configured so that: c1) without priority tostep b2), a user may use the manual control system in order to separateor bring the arm closer to the surface by means of the raising/loweringactuator and/or in order to incline the arm by means of the incliningactuator.
 17. Agricultural machine according to claim 10, wherein themachine is provided only with one single arm forming a spray boom of themachine.
 18. Agricultural machine according to claim 10, wherein: themachine is provided with several arms forming a spray boom of themachine, one of the arms forming a central frame of the boom and theother arms being articulated arms relative to the central frame, theraising/lowering actuator is configured for raising/lowering said armsby raising/lowering the central frame of the boom in translationrelative to the frame of the machine, and the machine is provided withseveral inclining actuators configured for inclining each of thearticulated arms relative to the central frame and configured forinclining the boom relative to the frame of the machine by means of thecentral frame.